X-ray analysis of samples is a growing area of interest across many industries such as consumer products, medical, pharmaceutical, and petroleum. The use of x-ray fluorescence, x-ray diffraction, x-ray spectroscopy, x-ray imaging, and other x-ray analysis techniques has led to a profound increase in knowledge in virtually all scientific fields.
X-ray fluorescence (XRF) is an analytical technique by which a substance is exposed to a beam of x-rays to determine, for example, the presence of certain components. In XRF, at least some of the elemental constituents of the substance exposed to x-rays can absorb x-ray photons and produce characteristic secondary fluorescence. These secondary x-rays are characteristic of the elemental constituents in the substance. Upon appropriate detection and analysis these secondary x-rays can be used to characterize one or more of the elemental constituents. XRF techniques have broad applications in many chemical and material science fields, including industrial, medical, semiconductor chip evaluation, petroleum, and forensics, among others.
As some examples of measurements required in the petroleum industry, trace levels of contaminants in petroleum feedstocks is a notorious problem in petroleum refining. Sulfur is a common component in crude oil streams—and its removal from final product is mandated due to its impact on the environment, as regulated by the US EPA under the Clean Air Act. Sulfur is harmful to the environment, and the cost of its removal is high. Therefore, monitoring sulfur levels early in the refining process is important. Chlorine and vanadium contaminants are considered “bad actors” by the refining industry for primarily non-regulatory, process control reasons. Chlorides also pose one of the greatest problems to the refining industry. According to a 2005 paper by The National Association of Corrosion Engineers (“NACE”): “Recently, an increasing number of refineries have experienced extreme corrosion and fouling in crude distillation unit overheads and/or naphtha hydrotreating units. The root causes were traced to severe spikes in the chloride levels.”
U.S. Pat. Nos. 6,934,359 and 7,072,439, hereby incorporated by reference herein in their entirety and assigned to X-Ray Optical Systems, Inc., the assignee of the present invention, disclose monochromatic wavelength dispersive x-ray fluorescence (MWD XRF) techniques and systems for the analysis of liquid samples.
As one particular example of a measurement system for such contaminants, the above-incorporated patents disclose techniques for the determination of the level of elements in petroleum fuels, and commercialized analyzers (e.g., SINDIE and CLORA) are now in widespread use for, e.g., sulfur and chlorine measurement at petroleum refining, pipeline, and/or terminal facilities.
XRF testing can take place off-line, i.e., using a bench-top, laboratory-type instrument to analyze a sample. In contrast to off-line analysis, on-line analysis provides “real-time” monitoring of sample composition at various points in the manufacturing process.
In either analyzer, for liquified petroleum gas (LPG) applications, fluids under particularly high pressure must be presented to the analyzer at a stable pressure. These “liquified gas” applications required the liquid to stay under pressure, e.g., 200-200 PSI, when presented to the analyzer.
What is required, therefore, are sample handling techniques and apparatuses for analysis systems handling high pressure, liquified samples, which provide analyte measurement results.